The present invention relates to a differential signal transmission circuit, a disk array controller, and a differential signal transmission cable.
Circuits and cables with differential signal transmission paths are known. There is known a technology for transmitting differential signals using such circuits and cables, where a transmission state of a differential signal is detected and high-frequency vibration of a transmitter is suppressed in order to avoid damage or breaking of the transmitter. For example, as information on a drive status of the transmitter, a receiver uses a DC component detected by a detector (see Japanese Translation of PCT Application No. 2003-517773, for example).
A circuit and a cable having a differential signal transmission path is incorporated and used in housings of a variety of apparatuses. Therefore, it is not easy for a repairer to open a housing equipped with the circuit and cable, in case of a data transfer failure. There was no easy method to confirm whether the data transfer failure was due to, for example, breaking of the differential signal transmission path.
Moreover, there was no method for a worker to non-visually inspect whether or nota unit was correctly connected using the cable having the differential signal transmission path. Thus, there is a limit on the accuracy of inspection. There were cases where an error occurs when activating an apparatus equipped with the unit and the connection of the cable was found to be incorrect.
In addition, according to the technology described in Japanese Translation of PCT Application No. 2003-517773, the information on the drive status of the transmitter can be obtained. However, it is not enough to apply power to the transmitter in order to obtain this information, and this technology therefore needs to carry out a process of applying power to the receiver as well and thereafter acquiring the information on the drive status of the transmitter. This process, however, increases the number of steps related to the inspection.